ANN ARBOR — As toxin-producing algal blooms similar to those that foul western Lake Erie each summer continue to rise exponentially throughout the world, a growing body of scientific data is emerging that shows they are getting harder to control because of climate change, invasive species, and global trade.
Their potential long-term impact on humans also means more cancer risk — not just short-term stomach cramps and diarrhea — and there needs to be a greater research emphasis on the role of nitrogen in driving up their toxicity, according to a variety of scientific presentations made Tuesday at the University of Michigan.
Don’t assume you’re safe limiting your fish consumption or contact with the water, either.
More is being learned about inhalation of airborne particles as an exposure pathway, said Lorraine Backer, senior scientist/environmental epidemiologist for the U.S. Centers for Disease Control and Prevention’s National Center for Environmental Health.
She said a study at two other bodies of water found a small amount of the algal toxin microcystin on nasal swabs of some participants — not enough to endanger their health, but evidence of inhalation exposure.
Jiyoung Lee, Ohio State University environmental health sciences associate professor, said she has found vegetables such as carrots and green beans are able to uptake minute levels of algal toxins when sprayed with water containing them. She also said walleye and other fish developed cancerous liver tumors in lab tests.
Ohio Sea Grant and OSU Stone Laboratory Director Chris Winslow said a research project is being assembled with Lake Erie charter boat captains to measure their airborne exposure levels while out on the water.
The presentations were made during the first day of the 2018 Science-Policy Confluence Conference organized by the Cooperative Institute for Great Lakes Research and the Chicago-based Environmental Law & Policy Center. The institute is a program headed on UM’s campus by the National Oceanic and Atmospheric Administration.
The second and final day is Wednesday, and will focus on policy initiatives. Toledo Mayor Wade Kapszukiewicz is to appear on the panel. Also expected to speak on Wednesday is ELPC Executive Director Howard Learner, whose group filed the federal lawsuit in Toledo that ultimately prompted the Kasich administration to reverse course and join Michigan in declaring western Lake Erie’s open water as impaired under the Clean Water Act, a move that will lead to tighter rules on agricultural runoff.
The Tuesday panels included Anna Michalak, a Stanford University global ecology professor, and Tim Davis, a Bowling Green State University associate professor who specializes in algae research. Both talked about the growing problem of algal blooms worldwide; Mr. Davis just returned from witnessing it up close at Africa’s Lake Victoria with two other BGSU colleagues, George Bullerjahn and Mike McKay.
Contrary to findings by some area scientists, including the University of Toledo’s Tom Bridgeman, internal loading of phosphorus — that which is carried over in Lake Erie from one year to the next — could be a large driver of algal blooms.
Ms. Michalak said her research into 30 years of data from this and other parts of the country has led her to believe “that internal recycling and loading of phosphorus might be a much stronger factor than we previously understood.”
But she and other scientists agreed the main issue remains agricultural runoff. They said it is more important than ever to limit concentrations of that because the Great Lakes region is becoming wetter and subject to more frequent, violent storms because of climate change.
Rick Stumpf, NOAA oceanographer, said northwest Ohio is getting on average nearly 2 more inches of rain each summer than it did 30 years ago.
That impact is expected to worsen because climate scientists have seen wet regions of the world getting wetter and dry areas getting drier, Ms. Michalak said.
“We can't just look at land management,” she said. “We have to look at that in the context of changing precipitation.”
And while experts at Ohio Sea Grant and Stone Lab have said in the past that western Lake Erie responds so quickly to nutrient reductions that a rapid turnaround could occur, Ms. Michalak and Mr. Davis said they expect the lake’s recovery to take a decade or more even if Ohio, Michigan, and Ontario hit their goal of reducing phosphorus concentrations into the lake 40 percent over 2008 levels by 2025.
“For reasons we can't yet explain, the recovery is likely to be slow, on the order of a decade or more,” Ms. Michalak said. “It’s actually more dramatic in other parts of the world, especially India and China.”
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